100 lines
3.0 KiB
C++
100 lines
3.0 KiB
C++
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// MCP4251 2-channel Digital Potentiometer
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// ww1.microchip.com/downloads/en/DeviceDoc/22059b.pdf
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#include <Arduino.h>
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#include <spi4teensy3.h>
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#ifndef Mcp4251_h
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#define Mcp4251_h
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class MCP4251
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{
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public:
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// You must at least specify the slave select pin and the rated resistance
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MCP4251(uint8_t slave_select, float rAB_ohms);
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// If you have measured wiper resistance, rW
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MCP4251(uint8_t slave_select, float rAB_ohms, float rW_ohms);
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// The resistance scaling, defaults to rAB_ohms
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float scale;
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// Read potentiometer values
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float wiper0();
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float wiper1();
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unsigned int wiper0_pos();
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unsigned int wiper1_pos();
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// Write potentiometer values
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void wiper0(float ohms);
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void wiper1(float ohms);
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void wiper0_pos(unsigned int wiper_pos);
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void wiper1_pos(unsigned int wiper_pos);
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// // Not implemented
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// // Connect / disconnect potentiometers
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// bool pot0_connected(bool terminal_a, bool wiper, bool terminal_b);
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// bool pot1_connected(bool terminal_a, bool wiper, bool terminal_b);
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// void pot0_connect(bool terminal_a, bool wiper, bool terminal_b);
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// void pot1_connect(bool terminal_a, bool wiper, bool terminal_b);
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//
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// bool pot0_shutdown();
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// bool pot1_shutdown();
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// void pot0_shutdown(bool shutdown);
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// void pot1_shutdown(bool shutdown);
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//
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// bool hw_shutdown();
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protected:
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// const static float rW_ohms_typical = 117.50f;
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const static unsigned int resolution_7bit = 128;
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const static unsigned int resolution_8bit = 256;
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// Other devices can be configured below vv as per the device numbering scheme:
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// MCP4N-- N=1 single pot, N=2 dual pot
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// MCP4--N N=1 potentiometer, N=2 rheostat
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// MCP4-N- N=3 7-bit volatile, N=4 7-bit non-volatile, N=5 8-bit volatile, N=6 8-bit non-volatile
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const static bool non_volatile = false;
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const static unsigned int resolution = resolution_8bit;
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float rW_ohms;
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float rAB_ohms;
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float rAW_ohms_max;
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uint8_t slave_select_pin;
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const static uint8_t kADR_WIPER0 = B00000000;
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const static uint8_t kADR_WIPER1 = B00010000;
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const static uint8_t kCMD_READ = B00001100;
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const static uint8_t kCMD_WRITE = B00000000;
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const static uint8_t kADR_VOLATILE = B00000000;
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const static uint8_t kADR_NON_VOLATILE = B00100000;
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const static uint8_t kTCON_REGISTER = B01000000;
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const static uint8_t kSTATUS_REGISTER = B01010000;
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uint16_t byte2uint16(byte high_byte, byte low_byte);
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byte uint16_high_byte(uint16_t uint16);
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byte uint16_low_byte(uint16_t uint16);
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void setup_ss(uint8_t slave_select_pin);
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void setup_resistance(float rAB_ohms, float rW_ohms);
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float step_increment();
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unsigned int ohms2wiper_pos(float ohms);
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float wiper_pos2ohms(unsigned int wiper_pos);
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uint16_t read(byte cmd_byte);
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void write(byte cmd_byte, byte data_byte);
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void wiper_pos(byte pot, unsigned int wiper_pos);
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};
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#endif // Mcp4251_h
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